Gastric interoception and gastric myoelectrical activity in bulimia nervosa and binge-eating disorder

Negative emotion differentiation, but not gastric interoception, is linked to "feeling fat" among women with elevated eating pathology

"Feeling fat" is the subjective sensation of being overweight, which is not fully explained by one's body weight. Disruptions in emotion differentiation and gastric interoception may contribute to feeling fat. We hypothesized that poor negative emotion differentiation and poor gastric interoceptive accuracy would each be associated with higher levels of feeling fat after adjusting for negative affect intensity and body fat percentage. Cisgender female university students (N = 69; M(SD) age = 20.3(3.7), 60.9 % heterosexual, 91.3 % white) completed questionnaires and the two-step water load test. Regression analyses, which adjusted for negative affect intensity and body fat percentage, found that neither negative emotion differentiation (B < 0.001, p = .52) nor gastric interoceptive accuracy (B = 0.01, p = .97) were related to feeling fat. Post hoc, eating pathology severity moderated the relationship between negative emotion differentiation and feeling fat (B = -6.97, p = .03); poorer negative emotion differentiation was associated with greater feeling fat for those with Eating Disorder Examination Questionnaire Global Scores above 1.47 (B = -5.79, p = .050). The relationship between gastric interoception and feeling fat did not vary by eating pathology severity (B = -0.04, p = .79). Self-reported feeling full also contributed to feeling fat after consuming water to perceived maximum fullness (p < .001); however, changes in feeling full were not associated with changes in feeling fat across the task (p = .09). Poorer negative emotion differentiation is associated with feeling fat for those with elevated eating pathology. Individuals with elevated eating pathology may benefit from improving their ability to label and understand emotions to reduce feeling fat. Future research should test whether changes in feeling full cause feeling fat.

Investigating the modulation of gastric sensations and disposition toward food with taVNS

Interoception, the perception of visceral sensations, is key for several survival functions, including those related to feeding behavior. Sensations of hunger and satiety are mediated by gastric signals transmitted via the vagus nerve to the Nucleus of Solitary Tract. Transcutaneous auricular vagus nerve stimulation (taVNS) has been shown to modulate brain-viscera communication and to impact interoceptive processing in the cardiac domain. Yet, its effect on gastric interoception remains unclear. The aim of this study was to investigate taVNS' modulatory effects on gastric interoception using the Water Load Test-II (WLT-II) and its impact on food-related dispositions through a disposition and willingness to eat task (DWET). Participants underwent active or sham taVNS while performing the WLT-II and DWET. Results showed no significant difference in gastric interoceptive accuracy and amount of water ingested between taVNS groups. However, we found a significant reduction in food liking after the fullness phase of the WLT-II in the active (vs sham) taVNS group, suggesting an influence of vagal activation in the inhibition of food enjoyment when satiated. These findings suggest that, while taVNS may not directly enhance gastric interoceptive accuracy at a conscious level, it influences food-related dispositions, likely by modulating the processing of gastric signals. Further research exploring the intricate relationship between vagal modulation, interoceptive abilities and eating behaviors is warranted to elucidate the underlying mechanisms and, possibly, develop targeted interventions for eating disorders.

Eating Pathology and Interoceptive Sensibility Using the Brief Multidimensional Assessment of Interoceptive Awareness-2: Can There be Too Much of a Good Thing?

This study evaluated the factorial structure and invariance of the Multidimensional Assessment of Interoceptive Awareness-v2 (MAIA-2). We also investigated incremental validity of the MAIA-2 factors for predicting eating pathology beyond appetite-based interoception. US-based online respondents (N = 1294; Mage=48.7 ± 18.4; 63% cis women; 78% White) were sampled. We conducted hierarchical stepwise regressions, dominance analysis, and multiple-group confirmatory factor analyses across age, gender, and eating disorder symptoms. An 8-factor, 24-item Brief MAIA-2 (BMAIA-2) model showed optimal fit. Using strict criteria (Δ CFI > 0.002), configural, metric, and scalar invariance were supported. After controlling for appetite-based interoception, higher scores on body listening, noticing, and emotional awareness unexpectedly predicted worse eating pathology, while higher scores on not worrying, not distracting, and trusting predicted less eating pathology, as hypothesized. Dominance analysis showed no subscales contributed >2% unique variance to global disordered eating beyond appetite-based interoception. For loss of control eating, however, not worrying was the dominant BMAIA-2 predictor, explaining 5% unique variance beyond appetite-based interoception. Research supported the relevance of multiple interoceptive sensibility dimensions captured by the BMAIA-2 to understanding eating-based pathology. Future studies should consider assessing its incremental validity using behavioral tasks and autonomic biomarkers of interoception to better understand the complex interplay among interoceptive skills and eating behavior.

Association of Dietary Intake with Interoception and Gastric Myoelectric Activity in Women with Binge Eating Disorder and Bulimia Nervosa

BACKGROUND

Women with binge eating disorder (BED) and bulimia nervosa (BN) usually consume high-calorie meals with variable macro- and micronutrient compositions and have a disturbed perception of gastric fullness. The association of dietary intake with gastric interoception and gastric myoelectric activity (GMA) is poorly studied. This study examined the link between GMA/interoception and dietary intake in women with eating disorders (ED) compared to age/body mass index (BMI)-matched controls.

METHODS

A total of 18 women diagnosed with BED (n = 9) or BN (n = 9) and 18 age/BMI-matched controls (MC) group were enrolled in this study. Interoception was measured by measuring the volume of ingested water until the feeling of maximal fullness within 5 minutes (5 min water load test; 5 min WL). GMA was measured using transcutaneous electrogastrography (EGG) before and after water ingestion. Dietary intake was recorded using the multipath 24-hour recall of the two proceeding days. Then, food processor software was used to analyze the macro- and micronutrient composition of their diets. The volume of water load (WL) and the EGG's average dominant frequency (ADF) were correlated with macro- and micronutrient intakes.

RESULTS

Compared to the matched controls, women with ED had a significantly higher consumption of total calories, fat, saturated fat, carbohydrate (CHO), fibers, and sugar, with further higher intakes of total calories and trans-fat in the BED compared to the BN subgroup (p < 0.05). Moreover, the BED group showed higher vitamin B1, copper, and iron intakes than the MC group (p-values were <0.05). The volume of 5 min WL was higher in the BN group than in the control group (697.50 ± 186.45 vs. 466.67 ± 120.44 mL; p < 0.05) and the BED group (697.50 ± 186.45 vs. 488.75 ± 152.17 mL; p < 0.05). In the BED group, ADF showed a significant positive correlation with CHO, sugar, and vitamin B12 intakes (r = 0.700, 0.719, and 0.766, respectively; p < 0.05). Additionally, the 5 min WL volume was negatively correlated with the fiber and sodium intake in the BN group (r = -0.710 and -0.724, respectively; p < 0.05).

CONCLUSION

Specific dietary approaches might be effective for women with BN and BED. Women with BN may benefit from diets that are higher in fiber and sodium. In contrast, those with BED may find diets rich in simple carbohydrates and vitamin B12 helpful for regulating their eating habits and gastric mobility. Future research is encouraged to test this finding prospectively.

Development and Psychometric Validation of the Body Trust Scale

Interoception (e.g., abilities to recognize/attend to internal sensations) is robustly associated with psychopathology. One form of interoception, body trust, is relevant for the development of disordered eating and suicidal thoughts/behaviors. However, measures of body trust are narrow, despite research suggesting body trust is multifaceted. The aim of this study was to develop a comprehensive measure of body trust: The Body Trust Scale (BTS). 479 U.S. adults completed self-report surveys containing the BTS and psychopathology measures. Exploratory and confirmatory factor analyses revealed a three-factor structure: Comfort with One's Body, Physical Attractiveness, and Comfort with Internal Sensations. Factors showed strong construct, convergent, and divergent validity, as well as moderate predictive validity for suicidal thoughts/non-suicidal self-injury. Furthermore, factors showed strong internal consistency, test-retest reliability, and were invariant across the gender binary. The BTS can be used in research and clinical settings to understand how specific facets of body trust relate to psychopathology.

Early change in gastric-specific anxiety sensitivity as a predictor of eating disorder treatment outcome

Eating disorders (EDs) are often accompanied by gastrointestinal (GI) distress. Anxiety sensitivity is the tendency to interpret sensations of anxiety as threatening or dangerous, and includes both broad physical symptoms (e.g., elevated heartrate) and GI-specific symptoms. Physical and GI-specific anxiety sensitivity may be important risk and maintaining factors in EDs. This study tested the hypothesis that greater reductions in both types of anxiety sensitivity during the first month of treatment would predict lower ED symptoms and trait anxiety at discharge and 6-month follow-up. Patients (n = 424) in ED treatment reported physical and GI-specific anxiety sensitivity, ED symptoms, and trait anxiety at treatment admission, 1-month into treatment, discharge, and 6-month follow-up. Analyses were conducted with hierarchical linear regression with imputation, controlling for relevant covariates. Results indicated that early reduction in GI-specific but not general physical anxiety sensitivity predicted both lower ED symptoms and lower trait anxiety at discharge and 6-month follow-up. These findings demonstrate the importance of GI-specific anxiety sensitivity as a potential maintaining factor in EDs. Developing and refining treatments to target GI-specific anxiety sensitivity may have promise in improving the treatment not only of EDs, but also of commonly co-morbid anxiety disorders.

Perceptual Dysfunction in Eating Disorders

Eating disorders (EDs) are characterized by abnormal responses to food and weight-related stimuli and are associated with significant distress, impairment, and poor outcomes. Because many of the cardinal symptoms of EDs involve disturbances in perception of one's body or abnormal affective or cognitive reactions to food intake and how that affects one's size, there has been longstanding interest in characterizing alterations in sensory perception among differing ED diagnostic groups. Within the current review, we aimed to critically assess the existing research on exteroceptive and interoceptive perception and how sensory perception may influence ED behavior. Overall, existing research is most consistent regarding alterations in taste, visual, tactile, and gastric-specific interoceptive processing in EDs, with emerging work indicating elevated respiratory and cardiovascular sensitivity. However, this work is far from conclusive, with most studies unable to speak to the precise etiology of observed perceptual differences in these domains and disentangle these effects from affective and cognitive processes observed within EDs. Further, existing knowledge regarding perceptual disturbances in EDs is limited by heterogeneity in methodology, lack of multimodal assessment protocols, and inconsistent attention to different ED diagnoses. We propose several new avenues for improving neurobiology-informed research on sensory processing to generate actionable knowledge that can inform the development of innovative interventions for these serious disorders.

Visceral sensitivity, hunger responsiveness, and satiety responsiveness: Associations between facets of gastrointestinal interoception and disordered eating profiles in an undergraduate sample

This preregistered study examined associations between empirically derived profiles of disordered eating in a diverse nonclinical sample and three facets of gastrointestinal (GI) interoception (visceral sensitivity, hunger responsiveness, satiety responsiveness). University students (n = 591; 53.3% women; 23.0% Hispanic) completed the Visceral Sensitivity Index, Adult Eating Behavior Questionnaire, and Eating Pathology Symptom Inventory. Latent profile analysis was conducted in Mplus v8.3 with four behavioral indicators (restricting, binge eating, excessive exercise, purging [binary]). Facets of GI interoception predicting odds of disordered eating profile membership compared to an asymptomatic group were evaluated. Five profiles were identified. Facets of GI interoception differentially predicted odds of membership in disordered eating profiles. However, higher scores on all three facets of GI interoception were associated with increased odds of membership in a high disordered eating profile. The relationship between distinct facets of GI interoception and specific disordered eating patterns appears nuanced, though individuals displaying a range of disordered eating behaviors may exhibit broad GI interoceptive dysfunction. Findings are consistent with the recent emphasis on idiographic treatment approaches for disordered eating and may have implications for screening among university students. Prospective longitudinal work and extension to clinical samples is needed.

The qualitative evaluation of food addiction across the lifespan

Although it remains controversial, food addiction (FA) research has expanded substantially and empirical evidence for FA is growing. While quantitative studies have explored the prevalence and correlates of FA during childhood and adolescence, little is known about the perceived lived experience of FA across the lifespan, nor how experiences and perceptions of FA may change over time. For this study, 16 participants who met symptom threshold criteria for FA on the Yale Food Addiction Scale 2.0 completed in-depth, semi-structured qualitative interviews focused on their perceptions of the development of FA overtime, and perceived risk and protective factors. Thematic analysis was used to develop themes about the lived experience of FA in childhood, adolescence, and adulthood. Overall, highly palatable foods were viewed as the most problematic, while minimally processed foods were less associated with impairment and distress. Themes in childhood included a strong desire for highly processed foods and the perception that parental control over food choices could be either protective or risky for the later development of FA depending on which foods were available at home. In adolescence and young adulthood, increasing autonomy over food choices and the high availability of highly processed foods in the college environment were viewed as risk factors. Additionally, weight gain was a prominent theme. Finally, adulthood was characterized by more severe manifestations of FA, and the stress of adult responsibilities (e.g., work, parenting) contributed to this perception. This research sets the stage for future quantitative studies to explore these novel findings at the population level.

Preliminary data that psychological treatment and baseline anxiety are associated with a decrease in postprandial fullness and early satiation for individuals with bulimia nervosa and related other specified feeding or eating disorder

OBJECTIVE

Gastrointestinal symptoms, particularly postprandial fullness, are frequently reported in eating disorders. Limited data exist evaluating how these symptoms change in response to outpatient psychological treatment. The current study sought to describe the course of postprandial fullness and early satiation across psychological treatment for adults with bulimia nervosa and related other specified feeding or eating disorders and to test if anxiety moderates treatment response.

METHODS

Secondary data analysis was conducted on questionnaire data provided by 30 individuals (80% white, M(SD)age  = 31.43(13.44) years; 90% female) throughout treatment and six-month follow-up in a pilot trial comparing mindfulness and acceptance-based treatment with cognitive-behavioral therapy for bulimia nervosa. Participants completed items from the Rome IV Diagnostic Questionnaire for Adult Functional Gastrointestinal Disorders and the State Trait Anxiety Inventory.

RESULTS

Postprandial fullness and early satiation both significantly decreased over time (ds = 1.23-1.54; p's < .001). Baseline trait anxiety moderated this outcome, such that greater decreases were observed for those with higher baseline anxiety (p = .02).

DISCUSSION

Results extend prior work in inpatient samples by providing preliminary data that postprandial fullness and early satiation decrease with outpatient psychological treatment for bulimia nervosa. Baseline anxiety moderated this effect for postprandial fullness. Future work should replicate findings in a larger sample and test anxiety as a mechanism underlying postprandial fullness in eating disorders.

PUBLIC SIGNIFICANCE

The current study found that common gastrointestinal symptoms (postprandial fullness and early satiation) decrease over the course of outpatient psychotherapy for adults with full and subthreshold bulimia nervosa. Postprandial fullness decreased more across time for those high in anxiety.

Application of electrogastrogram in assessment of gastric motility in acute pancreatitis

Background: Electrogastrogram (EGG) can reflect gastric motility disorders in many diseases, but its application in acute pancreatitis (AP) has not been studied. Therefore, our study aimed to investigate the value of EGG in assessing the existence of gastric motility disorder in patients with AP and in predicting the severity of AP. Methods: Patients with AP admitted to the First Affiliated Hospital of Nanchang University from June 2020 to December 2020 were enrolled. Five EGG parameters (Percentage of normal gastric slow wave (PNGSW), main frequency, average frequency, percentage of gastric tachycardia (PGT), percentage of gastric bradycardia (PGB)) were collected. The receiver operating characteristic (ROC) curve was constructed to judge the predictive value of EGG parameters to AP severity. Results: The PNGSW in AP patients was significantly lower than that of the control group (p < 0.05), and the PGB was higher in AP patients than that of the control group (p < 0.05). The area under curve (AUC) of the PNGSW and the PGB in diagnosing non-mild acute pancreatitis (N-MAP) were 0.777 (95% CI: 0.676-0.877, p < 0.001) and 0.775 (95% CI: 0.670-0.879, p < 0.001) respectively. After combining with C-reactive protein, the accuracy, sensitivity and specificity of predicting N-MAP were improved. Conclusion: EGG parameters can well reflect the gastric motility disorder of AP patients. The PNGSW and the PGB can be used to predict the occurrence of N-MAP.

Lower gastric sensitivity in quiescent inflammatory bowel disease than in irritable bowel syndrome

OBJECTIVE

Visceral hypersensitivity is considered a key symptom in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), both of which seriously affect health-related quality of life (HrQoL). Previous findings are mostly based on invasive procedures that may interfere with the assessment of visceral perception. The current study, therefore, investigates whether IBD and IBS are characterized by altered perception of 'natural' gastric distensions ('interoception').

METHODS

Twenty IBD patients in remission (13 Crohn's disease, 7 ulcerative colitis), 12 IBS patients, and 20/12 matched healthy control (HC) individuals, respectively, underwent the water load test, in which they could drink ad libitum until the subjective thresholds of satiation (stage 1) and fullness (stage 2) were reached. Gastric motility was assessed using electrogastrography.

RESULTS

IBD patients drank significantly more water until satiation than IBS patients, whereas no differences between patients and HC groups were observed. Electrogastrographic patterns were comparable between groups, suggesting no pathologies in gastric motility in IBD or IBS. The amount of water consumed until satiation negatively correlated with HrQoL related to bowel symptoms in IBD patients, but was positively associated with emotional well-being in IBS patients.

CONCLUSION

Our findings implicate relative gastric hypersensitivity in IBS, and relative hyposensitivity in IBD patients, which are both related to specific HrQoL aspects.

Gastric Myoelectric Activity and Body Composition in Women with Binge Eating Disorder and Bulimia Nervosa: A Preliminary Trial Study

Women with eating disorders (EDs) often complain of abnormal gastric responses, which may impact their eating patterns and, consequently, their body composition. Binge eating disorder (BED) and bulimia nervosa (BN) have been shown to affect gastric myoelectric activity (GMA), which may provide a basis for the gastric response in this disease population. This study aimed to examine GMA and body composition in patients with an ED compared to age-body mass index (BMI) matched controls. This case-control study included 18 adults diagnosed with BED or BN compared to 19 age-gender-BMI-matched controls. The electrogastrography with water load test was used to measure GMA during fasting and after water loading to satiety. Body composition was measured using a bioelectric impedance analyzer. The results showed that the ED group had a significantly higher water load than the control group and increased percentages of tachygastria times. Comparing the BED and BN subgroups showed differences in body composition status between the subgroups in the form of less fat mass, muscle mass, and total body water in the BN subgroup. In the BN subgroup, fat mass was associated with the average dominant frequency in the EGG. Thus, measuring GMA may be a promising approach to understanding gastric abnormalities in patients with EDs. Therapies targeting improving body composition in women with BED and BN are recommended in future ED management strategies.

Examination of the two-step water load test as a measure of gastric interoception and associations with eating and weight/shape concerns in a nonclinical sample

OBJECTIVE

The current study extended research examining the validity of the two-step Water Load Test (WLT-II), an objective, laboratory-based measure of gastric interoception, by investigating the validity of the WLT-II in a nonclinical sample and testing its contribution to the prediction of eating and weight/shape concerns.

METHODS

Participants (n = 129, 73.6% cisgender female, M = 20.13 years old) completed the WLT-II Questionnaire and two-step WLT-II, as well as self-report measures of eating and weight/shape concerns (Eating Disorder Examination Questionnaire; EDE-Q) and interoception (Multidimensional Assessment of Interoceptive Awareness-2; Intuitive Eating Scale-2 Reliance on Hunger and Satiety), in the lab at a large southeastern university. Data analysis included repeated measures ANOVA, correlations, and a series of hierarchical linear regressions.

RESULTS

Participants reported considerably more discomfort after the "maximum fullness" trial compared to the "satiation" trial. The WLT-II's objective measure of gastric interoception (sat_%) was not significantly correlated with the self-report measures of interoception and did not predict EDE-Q Dietary Restraint, Eating Shame, or Weight/Shape Concerns. Unexpectedly, greater gastric sensitivity was associated with less EDE-Q Preoccupation/Restriction. Exploratory analyses suggested a possible nonlinear association.

DISCUSSION

These results support the validity of the WLT-II in its ability to create, measure, and distinguish between the states of satiation and maximum fullness. However, results also suggest additional work is needed to better understand what the WLT-II's sat_% measure is capturing, as well as investigate potential nonlinear associations of the WLT-II with disordered eating.

PUBLIC SIGNIFICANCE

Interoception, or the processing of internal body signals, shows important links to disordered eating. Despite the clear relevance of gastric interoception to disordered eating-such as the ability to detect satiety signals-existing research has relied on general, self-report measures of interoception. This study examined the utility of a laboratory-based measure of gastric interoception. Results suggested mixed support for its validity and utility for predicting eating and weight/shape concerns in a nonclinical population.

Cardiac and Gastric Interoceptive Awareness Have Distinct Neural Substrates

Interoceptive awareness, an awareness of the internal body state, guides adaptive behavior by providing ongoing information on body signals, such as heart rate and energy status. However, it is still unclear how interoceptive awareness of different body organs are represented in the human brain. Hence, we directly compared the neural activations accompanying attention to cardiac (related to heartbeat) and gastric (related to stomach) sensations, which generate cardiac and gastric interoceptive awareness, in the same population (healthy humans, N = 31). Participants were asked to direct their attention toward heart and stomach sensations and become aware of them in a magnetic resonance imaging (MRI) scanner. The results indicated that the neural activations underlying gastric attention encompassed larger brain regions, including the occipitotemporal visual cortices, bilateral primary motor cortices, primary somatosensory cortex, left orbitofrontal cortex, and hippocampal regions. Cardiac attention, however, selectively activated the right anterior insula extending to the frontal operculum compared with gastric attention. Moreover, our detailed analyses focusing on the insula, the most relevant region for interoceptive awareness, revealed that the left dorsal middle insula encoded cardiac and gastric attention via different activation patterns, but the posterior insula did not. Our results demonstrate that cardiac and gastric attention evoke different brain activation patterns; in particular, the selective activation may reflect differences in the functional roles of cardiac and gastric interoceptive awareness.

Pilot study of a water load test as a measure of gastric interoception in anorexia nervosa

PURPOSE

Research and clinical experience suggest that individuals with anorexia nervosa (AN) have deficits in gastric interoception, which has been hypothesized to maintain restrictive eating. Behavioral water load tasks (WLTs) have the capability to noninvasively assess gastric interoception; however, to date, no studies have examined WLTs in AN. Thus, the present proof-of-concept pilot study explored the preliminary validity of a WLT in individuals with AN.

METHODS

Participants were n = 10 individuals with AN and n = 10 matched-control women (CW). Participants completed self-report questionnaires before and after a WLT, in which participants were asked to drink water until "completely full".

RESULTS

Participants with AN drank significantly less water than CW (AN = 240(109.14) milliliters (ml), CW = 398.00(149.21) ml, p = 0.02, Cohen's d = 1.21), but reported greater increases in negative affect pre- to-post-WLT (p = 0.04, partial eta² = 0.21). Correlations between WLT performance and interoceptive sensibility in AN and CW participants supported the convergent validity of the WLT.

CONCLUSION

Preliminary results support the potential utility of the WLT as a behavioral measure of gastric interoception in patients with AN. Future research should examine how response to the WLT changes over the course of intervention and how results are related to treatment outcome.

LEVEL OF EVIDENCE

Level IV: Evidence obtained from multiple time series analysis such as case studies. (NB: Dramatic results in uncontrolled trials might also be regarded as this type of evidence).

General versus hunger/satiety-specific interoceptive sensibility in predicting disordered eating

Dysfunctional interoceptive processing of hunger and satiety cues is particularly relevant to disordered eating behaviors. However, researchers often rely on general measures of interoceptive sensibility (IS¹; self-reported experience of internal bodily cues) which conflate interoceptive processes across biological systems (e.g., gastric, cardiac) when assessing the role of interoception in disordered eating. Participants (N = 213; 50% female, age M = 20.77 years) were recruited from a large southeastern university for this online study and completed the Intuitive Eating Scale-2 (hunger/satiety-specific), the Multidimensional Assessment of Interoceptive Awareness-2 (general), and the Eating Disorder Inventory Interoceptive Awareness Subscale (general) as measures of IS. The Eating Pathology Symptoms Inventory was used to assess disordered eating attitudes and behaviors. Controlling for sex and body mass index, hunger/satiety-specific IS was associated with binge eating, purging, and cognitive restraint over and above general IS measures and emerged as the dominant predictor of each. Hunger/satiety-specific IS did not predict restricting behavior. Dysfunctional processing of hunger and satiety cues may be a particularly important risk factor to target in screenings and interventions for disordered eating. Findings highlight the importance of careful selection of IS measures in research and targeting hunger/satiety-specific IS in clinical interventions for disordered eating.

Gastrointestinal Interoception in Eating Disorders: Charting a New Path

PURPOSE OF REVIEW

Abnormal interoception has been consistently observed across eating disorders despite limited inclusion in diagnostic conceptualization. Using the alimentary tract as well as recent developments in interoceptive neuroscience and predictive processing as a guide, the current review summarizes evidence of gastrointestinal interoceptive dysfunction in eating disorders.

RECENT FINDINGS

Eating is a complex process that begins well before and ends well after food consumption. Abnormal prediction and prediction-error signals may occur at any stage, resulting in aberrant gastrointestinal interoception and dysregulated gut sensations in eating disorders. Several interoceptive technologies have recently become available that can be paired with computational modeling and clinical interventions to yield new insights into eating disorder pathophysiology. Illuminating the neurobiology of gastrointestinal interoception in eating disorders requires a new generation of studies combining experimental probes of gut physiology with computational modeling. The application of such techniques within clinical trials frameworks may yield new tools and treatments with transdiagnostic relevance.

Gastric interoception and gastric myoelectrical activity in bulimia nervosa and binge-eating disorder

OBJECTIVE

Identifying factors that control food intake is crucial to the understanding and treatment of eating disorders characterized by binge eating. In healthy individuals, stomach distension plays an important role in the development of satiation, but gastric sensations might be overridden in binge eating. The present study investigated the perception of gastric signals (i.e., gastric interoception) and gastric motility in patients experiencing binge-eating episodes, that is, bulimia nervosa (BN) and binge-eating disorder (BED).

METHOD

Twenty-nine patients with BN or BED (ED group) and 32 age-, sex-, and BMI-matched healthy controls (HC group) participated in the study. The onset of satiation and stomach fullness were assessed using a novel 2-step water load test (WLT-II). Gastric myoelectrical activity (GMA) was measured by electrogastrography (EGG) before and after ingestion of noncaloric water.

RESULTS

Individuals in the ED group drank significantly more water until reporting satiation during the WLT-II. The percentage of normal gastric myoelectrical power was significantly smaller in the ED group compared to HC, and negatively related to the number of objective binge-eating episodes per week in patients with BN or BED. Power in the bradygastria range was greater in ED than in HC participants.

DISCUSSION

Patients with EDs have a delayed response to satiation compared to HC participants, together with abnormal GMA. Repeated binge-eating episodes may induce disturbances to gastric motor function.

Short-Term Fasting and Ingestion of Caloric Drinks Affect Heartbeat-Evoked Potentials and Autonomic Nervous System Activity in Males

Central nervous systems receive and process information from the internal and external environment to maintain homeostasis. This includes interoceptive awareness of the organism’s nutritional state. Whenever food supply is required, feelings of hunger initiate the search for and the consumption of appropriate amounts of nutrients. How this is physiologically regulated in humans has been subjected to research into interoceptive awareness of body states during fasting and food consumption. However, there is no research on the distinct effects of carbohydrate or protein intake on interoception. Therefore, we aimed to investigate the impact of fasting and consumption of standardized carbohydrate and protein shakes on interoception in a repeated-measures cross-over design in a sample of 37 healthy, normal weight males. As a physiological correlate of interoception, we measured heartbeat-evoked potentials (HEPs), which are suggested to reflect the cortical representation of cardiac signals, during eight-minutes resting state EEG-recordings. After a 16-hour fasting period, the HEP amplitudes were lower over right central and parietal electrodes and increased after ingestion of the nutritional shake. Exploratory analyses indicated that the difference between fasting and satiety was more prominent at carbohydrate compared protein testing days. Correlation analyses with heart rate variability (HRV) suggested that high cardiac sympathetic activity is related to lower HEP amplitudes. Furthermore, cardiac sympathetic activity and stress indices decreased from before to after the intervention, whereas HRV increased. Together, this study shows for the first time that fasting and the intake of a nutritional shake affects cardiac measures of autonomic nervous system functioning and the neural correlates of cardiac interoception. These findings could be relevant for diets and psychosomatic disorders, including eating disorders.

Female sweet-likers have enhanced cross-modal interoceptive abilities

There are well known phenotypic differences in sweet-liking across individuals, but it remains unknown whether these are related to broader underlying differences in interoceptive abilities (abilities to sense the internal state of the body). Here, healthy women (N = 64) classified as sweet likers (SLs) or sweet dislikers (SDs) completed a bimodal interoception protocol. A heartbeat tracking and a heartbeat discrimination task determined cardiac interoception; both were accompanied by confidence ratings. A water load task, where participants consumed water to satiation and then to maximum fullness was used to assess gastric interoceptive abilities. Motivational state, psychometric characteristics and eating behaviour were also assessed. SLs performed significantly better than SDs on both heartbeat tasks, independently of impulsivity, anxiety, depression, and alexithymia. No differences in metacognitive awareness and subjective interoceptive measures were found. With gastric interoception, SLs were more sensitive to stomach distention, and they ingested less water than SDs to reach satiety when accounting for stomach capacity. SLs also scored higher on mindful and intuitive eating scales and on emotional eating particularly in response to negative stimuli; emotional overeating was fully mediated via interoceptive performance. Overall, our data suggest the SL phenotype may reflect enhanced responsiveness to internal cues more broadly.

Altered Interoceptive Perception and the Effects of Interoceptive Analgesia in Musculoskeletal, Primary, and Neuropathic Chronic Pain Conditions

Chronic pain (CP) severely disrupts the daily life of millions. Interoception (i.e., sensing the physiological condition of the body) plays a pivotal role in the aetiology and maintenance of CP. As pain is inherently an interoceptive signal, interoceptive frameworks provide important, but underutilized, approaches to this condition. Here we first investigated three facets of interoceptive perception in CP, compared with pain-free controls. We then introduce a novel interoceptive treatment and demonstrate its capacity to reduce pain severity in CP, potentially providing complementary analgesic treatments. Study 1 measured interoceptive accuracy, confidence and sensibility in patients (N = 60) with primary, secondary musculoskeletal, and neuropathic CP. Compared with matched controls, CP participants exhibited significantly lower interoceptive accuracy and interoceptive confidence. Pain severity was predicted positively by interoceptive accuracy, anxiety and depression, and negatively by interoceptive confidence. Study 2 tested a promising new interoceptive treatment for CP, in a single-blind between-subjects design (N = 51) with primary, secondary musculoskeletal, and neuropathic CP patients. The treatment specifically activates the C-Tactile system, by means of controlled stimulation of interoceptive unmyelinated afferents, at 3 cm/s with a force of 2.5 mN. This treatment led to significant pain reduction (mean 23%) in the CP treatment group after only 11 min, while CP controls who received comparable but non-interoceptive stimulation reported no change in pain intensity. These studies highlight the importance of interoceptive approaches to CP and demonstrate the potential of this novel method of C-Tactile stimulation to provide complementary analgesic treatments.

Interoception, Stress, and Physical Symptoms in Stress-Associated Diseases

Abstract. The brain and peripheral bodily organs continuously exchange information. Exemplary, interoception refers to the processing and perception of ascending information from the body to the brain. Stress responses involve a neurobehavioral cascade, which includes the activation of peripheral organs via neural and endocrine pathways and can thus be seen as an example for descending information on the brain-body axis. Hence, the interaction of interoception and stress represents bi-directional communication on the brain-body axis. The main hypothesis underlying this review is that the dysregulation of brain-body communication represents an important mechanism for the generation of physical symptoms in stress-related disorders. The aims of this review are, therefore, (1) to summarize current knowledge on acute stress effects on different stages of interoceptive signal processing, (2) to discuss possible patterns of abnormal brain-body communication (i.e., alterations in interoception and physiological stress axes activation) in mental disorders and chronic physical conditions, and (3) to consider possible approaches to modify interoception. Due to the regulatory feedback loops underlying brain-body communication, the modification of interoceptive processes (ascending signals) may, in turn, affect physiological stress axes activity (descending signals), and, ultimately, also physical symptoms.

Body mistrust bridges interoceptive awareness and eating disorder symptoms

Interoceptive awareness (IA), or the awareness of internal body states, is known to be impaired in individuals with eating disorders (EDs); however, little is understood about how IA and ED symptoms are connected. Network analysis is a statistical approach useful for examining how symptoms interrelate and how comorbidities may be maintained. The present study used network analysis to (1) test central symptoms within an IA-ED network, (2) identify symptoms that may bridge the association between IA and ED symptoms, and (3) explore whether central and bridge symptoms predict ED remission at discharge from intensive treatment. A regularized partial correlation network was estimated in a sample of 428 adolescent (n = 187) and adult (n = 241) ED patients in a partial hospital program. IA was assessed using items from the Multidimensional Assessment of Interoceptive Awareness, and ED symptoms were assessed using items from the Eating Disorder Examination-Questionnaire. Central symptoms within the network were strong desire to lose weight, feeling guilty, and listening for information from the body about emotional state. The most central symptom bridging IA and ED symptoms was (not) feeling safe in one's body. Of the central symptoms, greater desire to lose weight predicted lower likelihood of remission at treatment discharge. Bridge symptoms did not significantly predict remission. Body mistrust may be a mechanism by which associations between IA and EDs are maintained. Findings suggest targeting central and bridge symptoms may be helpful to improve IA and ED symptoms. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Gastric Necrosis After Binge Eating in Bulimia: Recovery From Eating Disorder After Total Gastrectomy

BACKGROUND

Gastric necrosis following acute gastric dilatation is rare but more common in females with eating disorders, such as anorexia nervosa or bulimia, during which patients often alternate restriction and binge eating behaviors.

CASE PRESENTATION

A 37-year old female patient with a history of 15 years of bulimia nervosa was admitted to the emergency department 24 h after binge eating. Abdominal Computed Tomography imaging showed major gastric distension reaching the pelvis and compressing the digestive organs. Total gastrectomy was required because of gastric necrosis. The patient reported significant reduction in bulimic symptoms after gastrectomy.

CONCLUSION

We discuss here the possible mechanisms underlying this recovery, including changes in gut-derived factors that could mediate eating behavior changes.